The PROMIS Laboratory has been involved in the full implementation of the computerized Problem Oriented Medical Record on a single ward and the associated ancillary services. This proposal deals with the extension of such a problem oriented information system to a whole institution, in a manner that allows easy extension to the region and the full complex of health services. The above goal will be realized by implementation of the following principles: 1. The basis for the health care information system is a single, unit health record kept for each member of the population for his entire life span. 2. The unit health record is organized so that all problems are immediately apparent, and so that not only what was done for each problem but why it was done and what the results were are discernible. 3. The basic tool medical personnel use to create the unit health record had built it the currency of information and parameters of guidance reducing the user's into dependence on memory while allowing him to participate in the systems' growth. Such a system requires computer technology to manage the massive amount of information. 4. The form in which the unit health records are stored in the system must allow efficient retrieval for both individual records and groups of records to be used in population studies. Preservation of recorded medical logic provides a feedback loop for audit of both the user's performance and the system's functioning. 5. The unit health record is accessible around the clock at all locations where health care is provided. 6. The system's building blocks (hardware, instrumentational software, medical content software) permit expansion or contraction to serve many different medical settings and geographic areas in a manner that keeps quality a constant as the scale of the operation varies.